One theory is that a fridge caught fire, with residents and workers at the site hearing loud bangs as gas bottles exploded. Speed restrictions were imposed on the M8 motorway nearby, but later lifted.

Donald Neilson, a fish merchant who witnessed the blaze, told the BBC: “It really was like a raging inferno through there at the far end. I ran back in and shouted to our staff, ‘Everybody get out right now’.”

More than 400 people who work at the market were evacuated and there were no reported casualties. However, the blaze is expected to disrupt supplies of fruit, vegetables, meat and fish for hundreds of shops, restaurants and cafes in the Glasgow area and western Scotland.

Firefighters work to subdue the flames. Photograph: Russell Cheyne/Reuters

Stuart Patrick, chief executive of the Glasgow Chamber of Commerce, said: “While we haven’t carried out any formal work on the economic work on the impact of the blaze, obviously for the companies based at the site it is devastating and, given the scale, will have a knock-on effect on supplies to the catering and hospitality industries all across the region.

“We are making contact with the city council to see what can be done to mitigate disruption in the aftermath while reaching out to our members to find out about how their operations have been affected.”

One major food wholesaler and supplier that uses Blochairn market, Total Produce, said it had diverted its Glasgow staff to its Edinburgh depot.

Jim McGhee, who owns a fruit and vegetable shop in Castle Douglas, a market town about 90 miles south of Glasgow, said he had been at the market at 2.30am to collect produce.

“I was there for about an hour and the fire alarms went off,” he told the BBC. “Within 10 minutes the fire had spread right through the bottom end of the market and gas cylinders were exploding. It was really quite bad.”

Efforts to extinguish the fire were initially hampered by low water pressure in the area. Scottish Water engineers were called out to help remedy the problem.